biology of the skin

Question 1

process in which epidermal cells progressively mature from basal cells to lifeless cells of the stratum corneum
(corneocytes)

Answer 1

keratinization

Question 2

uppermost layer of the epidermis, which comes into contact with the environment

Answer 2

stratum corneum

Question 3

Antimicrobial peptides such as defensins _____ and cathelicidins (_________)

Answer 3

antiviral; antimicrobial

Question 4

melanin-containing granules in skin cells, cover the nuclei of skin cells, forming an umbrella that
protects DNA against mutations, and reflects light back

Answer 4

melanosomes

Question 5

primary cell type in the epidermis,

accounting for 80% of total cells

Answer 5

keratinocytes

Question 6

Also known as stratum germinativum

Answer 6

stratum basale

Question 7

Processes in stratum basale layer include

Answer 7

Formation of mitotically active keratinocytes
Production of keratin filaments
Production of cohesion molecules

Question 8

Keratin filaments K5 and K14 function in

Answer 8

attachment of keratinocytes to the basal membrane

Question 9

where did the stratum spinosum get their name

Answer 9

spine-like appearance of the cell margins

Question 10

Site of generation of a number of structural components that will form the epidermal barrier

Answer 10

stratum granulosum

Question 11

cysteine-rich protein that forms the major

protein component of the cornified envelope

Answer 11

Loricrin

Question 12

natural moisturizing factor

Answer 12

Fillagrin

Question 13

Found only in thick skin (e.g. palms, soles of feet

Answer 13

Stratum Lucidum

Question 14

how does the stratum corneum form

Answer 14

Complete differentiation of granular cells results in stacked layers of anucleate, flattened cornified cells that

Question 15

flat anucleated cells bound

together by lamellated lipids

Answer 15

corneocytes

Question 16

Skin color is determined by

Answer 16

melanocytes

Question 17

We all have the same number of melanocytes; what

differs among races is

Answer 17

granule size

Question 18

Trigger for melanin production

Answer 18

exposure to sunlight

Question 19

loss of melanocytes

Answer 19

Vitiligo

Question 20

bronzing of skin

Answer 20

Addison’s disease

Question 21

Matrix contains

Answer 21

collagen, elastin, and reticular fibers

Question 22

Superior surface of the papillary layer contains ridges called

Answer 22

dermal papillae

Question 23

Immediately inferior to the epidermis

Answer 23

Papillary Layer

Question 24

Accounts for around 80% of dermal thickness

Answer 24

Reticular Layer

Question 25

Flexure lines are found at

Answer 25

areas where dermis is tightly anchored to deeper structures (e.g. joints)

Question 26

Damage to the reticular layer may cause

Answer 26

scarring

Question 27

function of Pacinian corpuscles

Answer 27

Vibration

Question 28

function of Meissner’s corpuscles

Answer 28

Tapping, flicker, and point discrimination

Question 29

Joint movement and stretch

Answer 29

Ruffini’s corpuscles

Question 30

Speed and direction of movement

Answer 30

Hair follicle receptors

Question 31

Vertical dimpling of nonhairy skin

Answer 31

Merkel’s discs

Question 32

Vertical dimpling of hairy skin

Answer 32

Tactile discs

Question 33

function of Mechano-insensitive slow conducting unmyelinated C fibers

Answer 33

itch

Question 34

Nociceptors

Answer 34

pain